ANOREXIA NERVOSA (AN)

ANOREXIA NERVOSA (AN) - Mary Muscari, PhD, RN, CRNP, CS
BASICS
DESCRIPTION
• Refusal to maintain normal body weight, with associated fear of weight gain, body image disturbance, and amenorrhea
• Restricting and binge-eating/purging subtypes
• System(s) Affected: Cardiovascular; Endocrine; Metabolic; Gastrointestinal; Nervous; Reproductive
GENERAL PREVENTION
Encourage rational attitude about nutrition and weight, minimize weight-related criticism and teasing, moderate overly high self-expectations, enhance self-esteem
EPIDEMIOLOGY
• Predominant age at onset: 13-18 years
• Predominant sex: Female > Male (20:1)
• Global distribution
Incidence
8-19 women, 2 men per 100,000 per year
Prevalence
1% in women, 0.1% in men
RISK FACTORS
• Female gender
• Perceived body image distortions
• Perfectionism, obsessionality, rigidity
• Negative self-evaluation
• Academic and other achievement pressure
• Participation in sports or artistic activities that emphasize leanness or involve subjective scoring
- Ballet, running, wrestling, figure skating, gymnastics, cheerleading, weight lifting
• Parental psychiatric disorder
Genetics
• Underlying genetic vulnerability likely, but not well understood
- 1st-degree female relative with eating disorder increases risk 6- to 10-fold.
PATHOPHYSIOLOGY
Complex relationship between biologic, psychological, and social factors that results in an unrealistic perception of fatness. Subsequent malnutrition leads to disorder of multiple organs.
ETIOLOGY
• Serotonin neuronal systems are implicated.
• Multifactorial withpsychological, biological, genetic, environmental, and social factors
ASSOCIATED CONDITIONS
• Mood disorder
• Social phobia, obsessive-compulsive disorder
• Substance abuse disorder
• High rates of cluster C personality disorders


DIAGNOSIS
SIGNS AND SYMPTOMS
• Onset may be insidious or stress related
• Amenorrhea (primary or secondary)
• Report feeling fat even when emaciated
• Preoccupation with body size, weight control
• Elaborate food preparation and eating rituals
• Extensive exercise
• Weakness, fatigue, cognitive impairment
• Hypothermia, cold intolerance
• Constipation, bloating, early satiety
• Dry skin, scalp hair loss, peripheral edema
• Lanugo hair on extremities, face, and trunk
• Growth arrest, delayed puberty
• Hypotension, bradycardia, murmurs
• Decreased bone density, fractures
History
Ascertain fear of weight gain and/or distorted body image.
Physical Exam
• Often normal
• Vital signs: Bradycardia, orthostatic hypotension, body weight 85% expected
• Cardiac: Dysrhythmias, midsystolic click of mitral valve prolapse
• Skin/extremities: Dry, lanugo, hair loss, edema
• Neurologic and abdominal exams: To rule out other causes of weight loss and vomiting
TESTS
Lab
• No specific test for AN. Most findings are related directly to starvation, dehydration
- All findings may be within normal limits.
• Low serum leuteinizing hormone, follicle-stimulating hormone; low T4 with normal TSH
• Abnormal liver enzymes
• Altered blood urea nitrogen, creatinine clearance; electrolyte disturbances
• Hypoglycemia, hypercholesterolemia, hypercortisolemia, hypophosphatemia
• Low sedimentation rate
• Anemia, leukopenia, thrombocytopenia
• 12-lead ECG to assess for prolonged QT
Imaging
Dual-energy x-ray absorptiometry (DEXA) of bone only if underweight for >6 months to assess for diminished bone density
Diagnostic Procedures/Surgery
• DSM-IV-TR criteria
- Refusal to maintain body weight at or above a minimally normal weight for age, height
- Intense fear of gaining weight even though underweight
- A disturbance in the way body weight/shape is experienced; undue influence of body on self-evaluation or denial of seriousness of low body weight
- Specific types
 Restricting: Not engaged in binge-eating or purging behaviors
 Binge-eating/purging type: Regularly engages in binge-eating or purging behaviors (see Bulimia information related to these behaviors)
• Screening tools: SCOFF questionnaire, Eating disorder Screen for Primary Care (ESP), Eating Attitudes Test (EAT), Eating Disorder Inventory (EDI)
Pathological Findings
• Osteoporosis/osteopenia, pathologic fractures
• Sick euthyroid syndrome
• Cardiac impairment
DIFFERENTIAL DIAGNOSIS
• Hyperthyroidism,adrenal insufficiency
• Inflammatory bowel disease
• Immunodeficiency, chronic infections
• Malabsorption, diabetes
• CNS lesion
• Bulimia; body dysmorphic disorder
• Depressive disorders with loss of appetite
• Anxiety disorder, food phobia
• Conversion disorder, schizophrenic disorder
ALERT
AN may exist concurrently with chronic medical disorders, such as diabetes, cystic fibrosis.
TREATMENT
GENERAL MEASURES
• Initial treatment goal geared to weight restoration; most are managed as outpatients
• Outpatient treatment
- Interdisciplinary team (primary care physician, mental health professional, nutritionist) (1,2)[B,C]
- Average weekly weight gain goal: 0.5-1.0 kg (1)[C] with stepwise increase in calories
- Cognitive behavioral and/or family-based therapy (2,3)[B]
- Focus on health, not weight gain alone.
- Build trust, treatment alliance,
- Involve patient in establishing diet and exercise goals.
- Challenge fear of uncontrolled weight gain; help the patient to recognize feelings that lead to disordered eating.
- In chronic cases, goal may be to achieve a safe weight rather than a healthy weight.
• Inpatient treatment
- If possible, admit to specialized eating disorders unit (4)[C]
- Monitor vital signs, cardiac function, watch for edema, rapid weight gain (fluid overload)
- Initial bed rest with supervised meals may be necessary.
- Stepwise increase in activity
- Tube feeding or total parental nutrition used only as last resort
- Supportive symptomatic care as needed
Diet
• Goal is stabilization at a healthy weight on a balanced diet with normal eating pattern
• Diminished ruminations about calories, weight; increased enjoyment
Activity
• Monitor activity.
• Stepwise increase as patient gains weight
• Focus on enjoyable activities rather than goal-oriented ones.
MEDICATION (DRUGS)
First Line
• No medications are available that effectively treat patients with AN, but antidepressants may benefit those with comorbid depression (5,6)[C].
• Selective serotonin-reuptake inhibitors such as fluoxetine (Prozac): 10-60 mg may
- Help prevent relapse after weight gain
- Treat comorbid depression or obsessive-compulsive disorder (1,4,6)[C]
- Attend to black box warnings concerning antidepressants and conduct appropriate informed consent if antidepressants are prescribed
Second Line
• Management of osteopenia
- Elemental calcium 1200-1500 mg/d plus MVI containing 800 IU of vitamin D (2,4)[C]
- No indication for bisphosphonates in AN (2)[C]
- Weak evidence for use of HRT (2)[C]
- Psyllium (Metamucil) preparations (1 tbsp) to prevent constipation
FOLLOW-UP
DISPOSITION
Admission Criteria
• Suggested physiologic values: Heart rate 40 bpm, BP 90/60, symptomatic hypoglycemia, potassium 3 mmol/L, temperature 97.0F (36.1C), dehydration, other cardiovascular abnormalities, weight 75% of the expected weight, rapid weight loss, lack of improvement while in outpatient therapy
• Suggested psychological indications: Poor motivation/insight, lack of cooperation with outpatient treatment, inability to eat, need for nasogastric feeding, suicidal plan or intent, severe coexisting psychiatric disease, problematic family environment
ALERT
Pediatric Considerations
• Children often present with nausea, abdominal pain, fullness, and inability to swallow.
• Additional indications for hospitalization: Heart rate 50 bpm, orthostatic BP, hypokalemia or hypophosphatemia, rapid weight loss even if weight not 75% below normal
Geriatric Considerations
Late-onset AN (>50) may be long-term disease, or triggered by death of loved one, marital discord, or divorce.
Discharge Criteria
Lower relapse rate when discharged at expected healthy weights
PROGNOSIS
• Prognosis: ~50% recover; 25% improved; 25% chronically ill
• Mortality: 5-7%
COMPLICATIONS
• Refeeding syndrome
• Cardiac arrhythmia; cardiac arrest
• Cardiomyopathy, congestive heart failure
• Delayed gastric emptying, necrotizing colitis
• Seizures, Wernicke encephalopathy, peripheral neuropathy, cognitive deficits
• Osteopenia, osteoporosis
Pregnancy Considerations
• Fertility may be affected.
• Increased risk for miscarriage, operative delivery, congenital malformations, and low-birth-weight infants; should be managed as high risk
PATIENT MONITORING
• Level of exercise activity
• Weigh weekly until stable, then monthly.
• Depression, self-esteem, suicidal ideation
REFERENCES
1. NICE. Eating disorderscore interventions in the treatment and management of anorexia nervosa, bulimia nervosa and related eating disorders. NICE Clinical Guideline no 9. London: NICE, 2004 (accessed 15 Feb 2006).
2. American Psychiatric Association. Practice Guideline for the Treatment of Patients with Eating Disorders, 3rd ed. 2006, June (accessed Dec 10, 2006).
3. Hay P, Bacaltchuk J, Claudino A, Ben-Tovim D, et al. Individual psychotherapy in the outpatient treatment of adults with anorexia. Cochrane Database Syst Rev. 2003;(4):CD003909.
4. Yager J, Anderson AE. Anorexia nervosa. N Engl J Med. 2005;353:1481-1488.
5. Berkman ND, Bulik CM, Brownley KA, et al. Management of eating disorders. Evidence report/technology assessment No. 135. (Prepared by the RTI International-University of North Carolina Evidence-Based Practice Center under Contract No. 290-02-0016.) AHRQ Publication No. 06-E010. Rockville, MD: Agency for Healthcare Research and Quality, April 2006.
6. Claudino A, Hay P, Lima M, et al. Antidepressants for anorexia nervosa. Cochrane Database Sys Rev. 2006;(1):CD04365.